I too am stuck in room 16504

[dlcatftwin]

Hi all,
Jack is

stuck

or if not, I do not know how to progress from here. Here's the picture. Jack is right next to the barricade, on its left side (see the big red arrow pointing to it. He climbed to it from directly below, with no way to go anywhere.
Is he stuck, or, am I :-?

Many thanks,
DLC